• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1998.09a
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• pp.31-35
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• 1998

지진해일 수치해석시 일반적으로 사용되어오던 Shuto의 유한차분모형(Goto ＆ Shuto, 1983)은, 천수방정식을 사용하고 파의 분산효과는 수치오차를 이용하여 고려하므로, 정해진 계산시간간격($\Delta$t)에 대해 수심에 따라 격자간격을 적절히 선택하여야 한다. 또한 Shuto 모형은 leap-frag 기법을 사용하므로, 격자 및 계산시간간격이 심해에서 수치분산을 위한 조건을 만족시켰다 할지라도, 천수화에 의해 파장이 점점 작아져 파수(k)가 $\pi$/$\Delta$x가 되는 수심(2$\Delta$x wave)에 이르면 파가 더 이상 진행하지 못하고 반사하게 되므로 실제 현상과는 다른 결과를 보이게 된다. (중략)

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.2 s.13
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• pp.71-76
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• 2004

To investigate the inundation of tsunamis in the vicinity of a circular island, a numerical model has been developed based on quadtree grids. The governing equations of the model are the nonlinear shallow-water equations. The governing equations are discretized explicitly by using a finite difference leap-frog scheme on adaptive hierarchical quadtree grids. The quadtree grids are generated around a circular island where refined with rectangular or circular domain. Obtained numerical results have been verified by comparing to available laboratory measurements of run-up heights. A good agreement has been achieved.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.2 s.25
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• pp.45-52
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• 2007

In this study, the flood inundations of the Nam River catchment running through the Uiryeong and Haman regions have been simulated using the numerical model based on quadtree grids. The nonlinear Saint Venant equation is employed as the governing equation for a numerical model in this study. The governing equations are discretized explicitly with a finite difference leap-frog scheme on adaptive hierarchical quadtree grids. Results from this study are compared with those of established numerical models such as the HEC-RAS and the FLUMEN. A numerical model is also simulated according to the frequency variations of flood event. Obtained numerical results show good agreements with them of commercial models. It is found from this study that the flood inundations in the studied area can be occurred at a 500 year frequency event.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.667-676
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• 2013

This study analyzed the energy demand, greenhouse gas emission and greenhouse gas reduction potential of Electronic Electrical components company. The LEAP model targeting long term energy plan was used to establish the most efficient plan for the companies by examining the climate change policy of government and the countermeasures by companies. A scenario was created by having 11 greenhouse gases reduction plans to be introduced from 2011 as the basic plan. Regarding input data, energy consumption by business place and by use, number of employee from 2009 to 2012, land area and change in number of business places were utilized. The study result suggested that approximately 13,800 TJ of energy will be spent in 2020, which is more than 2 times of 2012 energy consumption. When the integrated scenario based on the reduction plan of companies would be enforced, approximately 3,000 TJ will be reduced in 2020. The emission of greenhouse gases until 2020 was forecasted as approximately 760,000 ton $CO_2eq$. When the integrated scenario would be enforced, the emission will be approximately 610,000 ton $CO_2eq$, which is decrease by approximately 150,000 ton $CO_2eq$. This study will help the efficient responding of eElectronic Electrical components company in preparing detail report on objective management system and enforcement plan. It will also contribute in their image as environment-friendly companies by properly responding to the regulation reinforcement of government and greenhouse gases emission target based on environment policy.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.85-93
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• 2016

This study the efficiency of greenhouse gas reduction of 'low carbon car collaboration fund' and its alternative 'control of average fuel efficiency and greenhouse gas', and 'improving driving behavior' were analyzed by using LEAP, long term energy analysis model. Total 4 scenarios were set, baseline scenario, without energy-saving activity, 'low carbon car collaboration fund' scenario, 'fuel efficiency improving scenario', and 'improving driving behavior' scenario. The contents of analysis were forecast of energy demand by scenario and application as well as reduction of greenhouse gas emission volume, and the period taken for analysis was every 1 year during 2015~2030. Baseline scenario, greenhouse gas emission volume in 2015 would be 7,935,697 M/T and 13,081,986 M/T in 2030, increased 64.8%. The analysis result was average annual increase rate of 3.4%. The expected average annual increase rate of other scenarios was, 'low carbon car collaboration fund' scenario 1.7%, 'fuel efficiency improving' scenario 3.0%. and 'improving driving behavior' scenario 3.4%. and these were each 1.7%, 0.3%. 0.3% reduce from baseline scenario. The largest reduction was 'low carbon car collaboration fund' scenario, and there after were 'fuel efficiency improving scenario', and 'improving driving behavior' scenario.

• Journal of Climate Change Research
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• v.7 no.3
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• pp.341-349
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• 2016

This study is intended to set a greenhouse gas emission scenario based on green remodeling pilot project (Annex building of Seoul Customs Office) using LEAP model, a long-term energy plan analysis model, to calculate the energy saving and greenhouse gas emission till year 2035 as well as to analyze the effect of electric power saving cost. Total 4 scenarios were made, Baseline scenario, assuming the past trend is to be maintained in the future, green remodeling scenario, reflecting actual green remodeling project of Seoul Customs Office, behavior improvement and renewable energy supply, and Total scenario. According to the analysis result, the energy demand in 2035 of Baseline scenario was 6.1% decreased from base year 2013, that of green remodeling scenario was 17.5%, that of behavior improvement and renewable energy supply scenario was 21.1% and that of total scenario was 27.3%. The greenhouse emission of base year 2013 was $878.2tCO_2eq$, and it was expected $826.3tCO_2eq$, approx. 5.9% reduced, in 2035 by Baseline scenario. the cumulative greenhouse gas emission saving of the analyzing period were $-26.5tCO_2eq$ by green remodeling scenario, $2.8k\;tCO_2eq$ by behavior improvement and renewable energy supply scenario, and $2.0k\;tCO_2eq$ by total scenario. In addition the effect of electricity saving cost through energy saving has been estimated, and it was approx. 634 million won by green remodeling scenario and appro. 726 million won by behavior improvement and renewable energy supply scenario. So it is analyzed that of behavior improvement and renewable energy supply scenario would be approx. 12.7% higher than that of green remodeling scenario.

• Journal of Korea Water Resources Association
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• v.35 no.4 s.129
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• pp.443-452
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• 2002

The propagation of the 1983 Central East Sea Tsunami recorded as the most devastating tsunami during last decades across the East Sea is numerically simulated in this study h numerical model based on the shallow~water equations is employed. The physical dispersion is somewhat replaced by the numerical dispersion resulting from the leap-frog scheme. Traveling times of leading tsunamis are estimated and wane rays are calulated based on the Munk and Arthur(1952).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.2
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• pp.116-127
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• 2002

Most of finite difference numerical models for the simulation of tsunami propagation developed so for are based on the shallow-water equations which are frequently solved by the leap-frog scheme. If the grid size is properly selected, this numerical scheme gives a correct dispersion effect fur constant water depth. However, if the water depth changes, the dispersion effect of tsunamis can not be accurately considered at every grid point in the whole computational domain. In this study we improved the existing two-dimensional dispersion-correction finite difference numerical scheme. The present scheme satisfies the local dispersion relationships of tsunamis propagating over a slowly varying topography while using uniform grid size and time step. To verify the applicability of the improved numerical model, a tsunami due to 1983 East Sea central earthquake is simulated for Korean harbors with the tide gage records such as Sokcho, Mukho, Pohang and Ulsan in the East Sea. Numerical results of the 1983 tsunami are compared with the measured data and the accuracy of the present numerical model is evaluated.

• Water for future
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• v.24 no.4
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• pp.49-58
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• 1991

Flood routing in the Youngsan River was performed for the flood event of July, 1989 by two finite difference methods. The Saint Venant eq., a kind of hyperbolic partial differential equation is employed as governing equation and the explicit scheme (Leap Frog) and implicit scheme (Preissmann) are used to discretize the GE. As for the external boundary conditions, discharge and tidal elevation are upstream and downstream BC, respectively and estuary dam is included in internal BC. Lateral inflows and upstream discharges are the hourly results from storage function method, At Naju station, a Relatively upstream points in this river, the outputs are interpreted as good ones by comparing two numerical results of FDMs with the observed data and the calibrated results by storage function method. and two computational results are compared at the other sites, from middle stream and downstream points, and thus are considered reliable. Therefore, we can conclude from this research that these numerical models are adaptable in simulating and forecasting the flood in natural channels in Korea as well as existing hydrologic models. And the study about optimal gate control at the flood time is expected as further study using these models.

• Journal of Energy Engineering
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• v.18 no.4
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• pp.230-238
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• 2009

We study about small gas engine and fuel cell CHP (Combined Heat and Power) as the technologies for energy conservation and $CO_2$ emissions reduction. Korea government plans to use them in near future. This study quantitatively analyzed energy consumption and $CO_2$ emissions reduction potential of small CHP instead of existing electric power plant (coal steam, combined cycle and oil steam) using LEAP (Long-range Energy Alternative Planning system) as energy-economic model. Three future scenarios are discussed. In every scenario similar condition for each CHP is used. Alternative scenario I: about 6.34% reduction in $CO_2$ emissions is observed in 2019 due to increase in amount of gas engine CHP and fuel cell CHP while coal use in thermoelectric power plant is almost stagnant. In alternative scenario II: a small 0.8% increase in $CO_2$ emission is observed in 2019 keeping conditions similar to alternative scenario I but using natural gas in combined cycle power plant instead of coal. During alternative scenario II overall $CO_2$ emission reduction is observed in 2019 due to added heat production from CHP. Alternative scenario III: about 0.8% reduction in $CO_2$ emissions is observed in 2019 using similar CHP as AS I and AS II. Here coal and oil are used in thermoelectric power plant but the quantity of oil and coal is almost constant for next decade.